This report reviews the experience with 78 alimentary tract duplications found in 64 patients over a 40 year period at the Children's Hospital of Pittsburgh. Ten patients had the duplication discovered at autopsy. Multiple duplications were found in 15% of patients. The symptoms and physical findings of a duplication varied with location, size and mucosal pattern. About one-fifth of the duplications contained ectopic mucosa, usually gastric. Two-thirds of the patients were diagnosed prior to one year of age. Vertebral anomalies, as a clue to the presence of the lesion, were present in 15% of the patients. The most common indications for surgery included a mediastinal or abdominal mass, intestinal obstruction, and gastrointestinal bleeding. The results of surgery were favorable, with a mortality of 20%. Surgical complications accounted for six deaths, while four children died of severe associated anomalies. Three others died without surgical treatment, but with symptoms from the duplication.